In a radio communication system, the capacity of the channel increases with the increase of antennas. In order to obtain system capacity higher than the capacity of a single-antenna system, multiple antennas are set on the transmitter side and the receiver side of the MIMO transmission system, which improves the spectrum efficiency of the radio link and the reliability of the link. The channels in a multi-antenna system are called MIMO channels.
Generally, with more antennas and higher order of the modulation symbol, the MIMO receiver is more complex. Based on a Maximum-Likelihood (ML) detection algorithm, the complexity of calculation increases exponentially with the increase of transmitting antennas. In recent years, various methods are designed to reduce the complexity of the receiver, for example, Successive Interference Cancellation (SIC), feedback decision, Maximum A Posterior (MAP), and Sphere Detection (SD) algorithm. Generally, the ML detection algorithm may be simplified as an SD algorithm. The SD algorithm reduces complexity of the receiver on the basis of the ML detection algorithm. However, involving the need of searching out a solution closest to the transmitting vector, the SD algorithm is still rather complicated. In recent years, a Lattice-Reduction (LR) algorithm is put forward to further simplify the ML algorithm. The LR algorithm transforms the existing channel matrix to obtain an equivalent channel matrix. The equivalent channel matrix is similar to a diagonal matrix, and can detect LR domain signals through linear detection or SIC detection, and then map the LR domain signals to transmitting signals, which accomplishes better detection performance and simplifies the receiver drastically. Research reveals that the LR algorithm can obtain full diversity gain.
After analyzing the prior art, the inventor of the present invention finds that: The complexity of the LR algorithm in the prior art increases rapidly with the increase of its basis vectors. Therefore, in a large MIMO system, the detection based on an LR algorithm is still rather complicated, and is difficult to implement.